1 6* CRUSTACEA MAI,ACOSTRACA. IV. 



b. Endopod of the uropods distinctly or considerably shorter than the exopod. 



12. Leucon fulvus G. O. Sars. 



1865. Leucon julvus G. O. Sars, Forh. Vid. Selsk. Christiania for 1864, p. 180. 

 ! 1900. G. O. Sars, Account, III, p. 32, PI. XXIV. 



1911. Stappers, Camp. arct. Due D'Orleans, Crust. Malacost. p. 105, PI. IV, fig. 8. 



1913. Stabbing, Das Tierreich, 39. Lief. p. 66. 



This species was, according to Sars and Stappers, known only from depths between 6 and 50 fathoms, 

 thus a pronounced shallow-water form. The following list of localities shows nearly every desirable depth 

 between 10 and 582 fathoms, and even that a couple of specimens from nearly 1200 fath. are referred to 

 this species. I have spent a good deal of time in search for any reliable character, by which it would be possible 

 to refer the specimens from more than 50 or 100 fathoms to another species, but without result. In the carapace, 

 the antennulse, the thoracic legs of first and second pairs, and the uropods some variation in minute particulars 

 could be found, but no real difference indicating the possibility of dividing the form into two species. Only 

 one feature may be noted, viz. that the 2 specimens from Stat. 35, 362 fath., 4 of the 5 specimens from Stat. 

 25, 582 fath., and the majority of, but not all, specimens from Stat. 32, 318 fath., have some or several saw- 

 teeth on the dorsal edge of first and second free thoracic segments, while such teeth are absent in the 2 spec- 

 imens from Stat. 28, 420 fath., the 2 specimens from Stat. 126, 293 fath., the 2 young males from Stat. 24, 

 1199 fath., and in specimens from all places with the depth less than 200 fath. The existence of such dorsal 

 teeth on the anterior thoracic segments is consequently to be regarded as variation in specimens from con- 

 siderable depth. 



It may be mentioned that second joint of the exopod in the uropods is always at least rather long, 

 but frequently not as long in proportion to first joint as shown by Sars. Stappers states that he has found 4 

 lanceolate appendages on the ischium of third pair of thoracic legs in the adult males, and that these append- 

 ages are shorter than in the othet boreal or arctic forms examined by him ; this observation agrees completely 

 with males from 0nundar Fjord examined by me, and it is mentioned here, because G. O. Sars in 1865 has an- 

 other statement and in 1900 a third statement, both consequently wrong. 

 Occurrence. Taken by the "Ingolf" at 8 stations. 



Davis Strait: Stat. 32: Lat. 6635' N., Long. 5638' W., 318 fath., temp. 3.9; 9 specimens. 

 Stat. 31: Lat. 6635'N., Long. 5554' W., 88 fath., temp. 1.6; 4 specimens. 



Stat. 35: I,at. 65i6' N., Long. 55O5' W., 362 fath., temp. 3.6; 2 specimens. 

 Stat. 28: Lat. 65i4' N., Long. 5542' W., 420 fath., temp. 3.5; 2 specimens. 

 Stat. 25: Lat. 633o' N., Long. 5425' W., 582 fath., temp. 3.3; 5 specimens. 

 Stat. 24: Lat. 63o6' N., Long. 56oo' W., 1199 fath., temp. 2.4; 2 specimens (im- 

 mature males). 



North of Iceland: Stat. 128: Lat. 665o' N., Long. 2oO2' W., 194 fath., temp. 0.6; 24 specimens. 

 Stat. 126: Lat. 67i9' N., Long. I552' W., 293 fath., temp. -=- 0.5; 2 specimens. 



